Spring for biasing a rocker arm and mounting therefor



Sept. 6, 1966 M. L. THOMPSON 3,270,725

SPRING FOR BIASING A ROCKER ARM AND MOUNTING THEREFOR Filed Dec. 2, 1964INVENTOR. MA R/ON LEE 7/3 0MP50A/ BY MAHO/VEY, HALBEET 6:

HO/QA/BAKEE A 770E/VEYS United States Patent 3,270,725 SPRING FORBIASING A ROCKER ARM AND MOUNTING THEREFOR Marion Lee Thompson, 2734Eastvale, Rolling Hills, Calif. Filed Dec. 2, 1264, Ser. No. 415,392 6Claims. (Cl. 123-90) This invention relates to a spring component for anengine and more particularly, to a spring employed to exert a torque ona rocker arm so as to aid the rocker arm in following the movements of areciprocally acting push rod. This invention also relates to means formounting the spring on the rocker arm supporting the shaft, and on thehead of the rocker arm adjacent the push rod.

In applicants Patent No. 3,139,872, issued July 7, 1964, a spring forbiasing a rocker arm and a split-shaft seat for said spring aredisclosed. The present invention relates to a modified form of such aspring, to other seating means for such a spring, and to abutment meansfor mounting the spring on the rocker arm.

The primary object of the invention is to provide a spring andsimplified means for mounting the spring in association with a rocker.arm for an engine valve assembly, the spring being disposed so as toapply a torque to the rocker arm to cause the rocker arm to followclosely the movements of a push rod.

Another object of the invention is to provide such a spring and mountingmeans therefor whereby, particularly on the movement of the push rodaway from the rocker arm, the torquing action of the engines compressionspring on the rocker arm causing the rocker arm to pivot and follow thepush rod, will be aided and abetted by the rocker arm spring.

Yet another object of the invention is to provide a spring and mountingmeans therefor of the character described wherein the spring may beeasily, firmly, and :adjustably seated on the supporting shaft for therocker arm so as to provide selective adjustment of the torque exertedon the rocker arm by the spring.

A further object of the invention is to provide abutment means on therocker arm in the area of the abutment of the spring thereon, so thatwear of the rocker arm is resisted and longer effective life is impartedto the rocker arm.

A still further object of the invention is to provide such a springwhich may be firmly seated so as to be resistant to displacement whichmight otherwise occur due to shocks and vibrations from the engine.

Another object of the invention is to provide such a spring which iseasy and inexpensive to manufacture and install in association with arocker arm.

With these and other objects in view, the invention consists of theconstruction, arrangement, and combination of the various elements ofthe device whereby the objects contemplated are attained, as hereinafterset forth, pointed out in the appended claims, and illustrated in theaccompanying drawing, in which:

FIG. 1 is a side elevation view of the device of the present invention;

FIG. 2 is a top plan view of the device as illustrated in FIG. 1;

FIG. 3 is a perspective View of the shaft element of the device;

FIG. 4 is a fragmentary perspective view of the shaft element asillustrated in FIG. 3, but turned 90";

FIG. 5 is a fragmentary, side elevational view of an alternative form ofconstruction;

FIG. 6 is a top plan view of the device as illustrated in FIG. 5; and

3,276,725 Patented Sept. 6, 1966 FIG. 7 is an isometric view of thebuffer element illustrated in FIGS. 5 and 6.

A rocker arm 10 is pivotally mounted on a shaft 12 which in turn ismounted on an intersecting shaft 14 projecting from an engine housing(not shown). A push rod 16 abuts on the underside of the rocker arm 10adjacent one end 18 of the rocker arm 10. It will be understood that thepush rod 16 is mounted on the engine for reciprocal movement caused bythe action of a rotatable cam shaft disposed within the engine housing(not shown).

Disposed on the underside of the rocker arm 10 adjacent the other end 19thereof is an anvil 20 which bears on a reciprocating valve stem 22, inassociation with which a valve compression spring 24 is mounted.

The ends of the shaft 12 protrude beyond the rocker arm 10, and formedin the protruding ends of the shaft 12 are transverse slots 30 which,preferably, pass through the center of the shaft 12 and intersect eachother at that point. The slots 30 are disposed so as to receive andsecure anchors legs of a spring hereinafter described.

As illustrated in FIGS. 1, 3 and 4 of the drawing, two of said slots 30are provided at each end of the shaft 12 so that, selectively, the saidspring anchor legs may be mounted in one or the other of said slots,dependent on the spring torque desired. Although two slots 30 are shownin the drawing at each end of the shaft v12, it will be understood thatone slot or a larger plurality of slots may be provided, the two slotsbeing shown by way of illustration, and not by way of limitation.

An annular groove 32 is formed adjacent each end of the shaft 12, thegrooves 32 being disposed so as to receive and secure a C-ring,hereinafter described, or other retaining means for retaining the springanchors legs within the slots 30.

A spring, generally designated 40, embodies a pair of spaced-aparttorque producing ooils 42, in substantially axial alignment with eachother. As best shown in FIG. 1 of the drawing, each of the coils 42 maybe a double coil, but this is by way of illustration, and not by way oflimitation, because either a single coil or a larger plurality of coilsmay be provided. The free end of each coil 42 is straightened to providean anchor leg 44.

Each of the coils 42 has a cantilevered, internal extension or leg 46,which may be slightly arcuate, as best illustrated in FIG. 1, orsubstantially straight, the legs 46 being disposed substantiallyparallel to each other and extending upwardly when the spring is mountedin the position shown in FIG. 1. The legs 46 then bend to define asubstantially straight transverse yoke 48 disposed so as to abut on thetop of the rocker arm 10 in substantial alignment with the point ofabutment of the push rod 16 on the underside of the rocker arm 10.

To mount the spring 40 on the shaft 12 and the rocker arm 10, the yoke48 is positioned over the end 18 of the rocker arm 10, and the anchorlegs 44 are inserted in selected, aligned slots 30 on opposite ends ofthe shaft 12, dependent on the spring torque desired. C-rings 50 arethen mounted in the grooves 32. The grooves 32 being positionedexternally of the anchor legs 44, the C-rings 50 will secure the anchorlegs 44 in the slots 30, and the spring 40 will thus be firmly anchoredto the shaft 12, while the yoke 48 is in abutment with the upper side ofthe rocker arm 10.

As, by engine valve action, the valve stem 22 moves downwardly, againstthe biasing action of the compression spring 24, and the push rod 16moves upwardly, the rocker arm 10 will pivot on the shaft .12, with theend 19 of the rocker arm 10 following the valve stem 22.

As the rocker arm 10 pivots in that direction, torque will build up inthe spring 40. Then, as the valve stem 22 reaches the end of its strokeand commences to move reciprocally upwardly, while the push rod 16simultaneously commences to move downwardly, the torque in the spring 40will be applied to the end 18 of the rocker arm 1%) to cause thepivoting rocker arm 1&3 to follow closely the down stroke of the pushrod 16, while aiding the biasing action of the compression spring 24 onthe rocker arm 10.

Referring to FIGS. 1 and 2 of the drawing, there is shown a preferredform of reinforcing for the top side of the rocker arm 10 so as to makeit resistant to frictional wear in the area Where the yoke 48 of thespring 40 abuts on the rocker arm 10. A U-shaped plate 60, is provided.The plate 60 is made of metal which is substantially harder than themetal of Which the rocker arm 10 is constructed. The rocker arm 10 has acentrally disposed, elongate opening 62 therein. The plate 60 has itslegs 64 overlying the top side of the rocker arm 10 laterally of theopening 62, and has its body portion 66 overlying the top surface of theend 18 of the rocker arm 10. The plate 60 may be mounted on the rockerarm 10 by any suitable means, such as by screws 68, disposed adjacentthe free ends of the legs 64. It will thus be seen that the body 66 ofthe plate 60 will present a Wear-resistant abutting surface to the yoke48 of the spring 40. Consequently, the rocker arm 10, even though madeof a relatively light metal, will be assured of a long, effectiveoperational life, despite the torque exerted thereon by the spring 40.

In FIGS. 5-7 of the drawing, an alternative form of means of providingfriction wear-resistance is shown. A transverse groove 70, V-shaped incross-section, is formed on the top surface of the rocker arm adjacentthe end 18 on the line of abutment of the yoke 48 thereon. An elongate,hard metal clip 72, V-shaped in cross-section, is firmly disposed in thegroove 70, with its flat body portion aligned with, and preferablyslightly above, the plane of the top surface of the rocker arm 10. Theclip 72 is positioned so that the yoke 48 will abut thereon.

While the instant invention has been shown and described herein in whatis conceived to be the most practical and preferred embodiments, it isrecognized that departures may be made therefrom within the scope of theinvention, which is therefore not to be limited to the details disclosedherein, but is to be accorded the full scope of the claims so as toembrace any and all equivalent devices.

I claim:

1. In combination, an engine rocker arm assembly, a push rod, and aspring for torque biasing the rocker arm into substantially continuousengagement with the push rod, which combination comprises: a shaft; arocker arm pivotally mounted on the shaft, the ends of the shaftprotruding beyond the rocker arm; aligned, transverse slots formed inthe axially outwardly facing surfaces of the protruding ends of theshaft; a reciprocally movable push rod abutting on the underside of therocker arm adjacent one end of the rocker arm and adapted to pivot therocker arm on the shaft; a spring having a pair of parallel coils spacedapart from each other and adapted to produce a torque; a first,substantially straight leg extending from each of the coils, each ofsaid legs being adapted to be received in a transverse slot in anopposite end of the shaft; a second leg extending from each of saidcoils, said second legs being disposed substantially parallel to eachother; and a transverse yoke interconnecting the second legs and adaptedto overlie and abut on the rocker arm above the abutment of the push rodthereon, said yoke being in torque biasing engagement with the rockerarm so as to cause the rocker arm to follow the push rod in itsreciprocal movement.

2. The combination defined in claim 1, including means for securing thefirst legs of the spring in the slots in the shaft.

3. The combination defined in claim 1, including a plate of hard metaloverlying the rocker arm, said plate de fining a hard abutting surfacefor the spring yoke.

4. In combination, an engine rocker arm assembly, a

push rod, and a spring for torque biasing the rocker arm intosubstantially continuous engagement with the push rod, which combinationcomprises: a shaft; a rocker arm pivotal-1y mounted on the shaft, theends of the shaft protruding beyond the rocker arm; aligned, transverseslots formed in the axially outwardly facing surfaces of the protrudingends of the shaft; a reciprocally movable push rod abutting on theunderside of the rocker arm adjacent one end of the rocker arm andadapted to pivot the rocker arm on the shaft; a spring having a pair ofparallel coils spaced apart from each other and adapted to produce atorque; a first, substantially straight leg extending from each of thecoils, each of said legs being adapted to be received in a transverseslot in an opposite end of the shaft; a second leg extending from eachof said coils, said second legs being disposed substantially parallel toeach other; a transverse yoke interconnecting the second legs andadapted to overlie and abut on the rocker arm above the abutment of thepush rod thereon, said yoke being in torque biasing engagement with therocker arm so as to cause the rocker arm to follow the push rod in itsreciprocal movement; an annular groove in the shaft adjacent each end ofthe shaft; and a C-ring disposed in each of said grooves and protrudingtherefrom, the C-rings being disposed externally of the first legs ofthe spring and adapted to secure the first legs in the slots in theshaft.

5. In combination, an engine rocker arm assembly, a push rod, and aspring for torque biasing the rocker arm into substantially continuousengagement with the push rod, which combination comprises: a shaft; arocker arm pivotally mounted on the shaft, the ends of the shaftprotruding beyond the rocker arm; aligned, transverse slots formed inthe axially outwardly facing surfaces of the protruding ends of theshaft; a reciprocally movable push rod abutting on the underside of therocker arm adjacent one end of the rocker arm and adapted to pivot therocker arm on the shaft; a spring having a pair of parallel coils spacedapart from each other and adapted to produce a torque; a first,substantially straight leg extending from each of the coils, each ofsaid legs being adapted to be received in a transverse slot in anopposite end of the shaft; a second leg extending from each of saidcoils, said second legs being disposed substantially parallel to eachother; a transverse yoke interconnecting the second legs and adapted tooverlie and abut on the rocker arm above the abutment of the push rodthereon, said yoke being in torque biasing engagement with the rockerarm so as to cause the rocker arm to follow the push rod in itsreciprocal movement; an annular groove in the shaft adjacent each end ofthe shaft; a C-ring disposed in each of said grooves and protrudingtherefrom, the C-rings being disposed externally of the first legs ofthe spring and adapted to secure the first legs in the slots in theshaft; and a plate of hard metal overlying the rocker arm, said platedefining a hard, abutting surface for the spring yoke.

6. In combination, an engine rocker arm assembly, a push rod, and aspring for torque biasing the rocker arm into substantially continuousengagement with the push rod, which combination comprises: a shaft; arocker arm pivotally mounted on the shaft, the ends of the shaftprotruding beyond the rocker arm; aligned, transverse slots formed inthe axially outwardly facing surfaces of the protruding ends of theshaft; a reciprocally movable push rod abutting on the underside of therocker arm adjacent one end of the rocker arm and adapted to pivot therocker arm on the shaft; a spring having a pair of parallel coils spacedapart from each other and adapted to produce a torque; a first,substantially straight leg extending from each of the coils, each ofsaid legs being adapted to be received in a transverse slot in anopposite end of the shaft; a second leg extending from each of saidcoils, said second legs being disposed substantially parallel to eachother; a transverse yoke interconnecting the second legs and adapted tooverlie and abut on the rocker arm above the abutment of the push rodthereon, said yoke being in torque biasing engagement with the rockerarm so as to cause the rocker arm to follow the push rod in itsreciprocal movement; an annular groove in the shaft adjacent each end ofthe shaft; a C-ring disposed in each of said grooves and protrudingtherefrom, the C-rings being disposed externally of the first legs ofthe spring and adapted to secure the first legs in the slots in theshaft; a transverse groove of V-shape in crossasection formed on the topside of the rocker arm; and a hard metal clip of V-shape incross-section disposed in said groove and having its body protrudingtherefrom, the body of said clip being disposed so as to define a hard,abutting surface for the spring yoke.

References Cited by the Examiner UNITED STATES PATENTS 10 MARK NEWMAN,Primary Examiner.

A. I. SMITH, Assistant Examiner.

1. INCOMBINATION, AN ENGINE ROCKER ARM ASSEMBLY, A PUSH ROD, AND ASPRING FOR TORQUE BIASING THE ROCKER ARM INTO SUBSTANTIALLY CONTINUOUSENGAGEMENT WITH THE PUSH ROD, WHICH COMBINATION COMPRISES: A SHAFT; AROCKER ARM PIVOTALLY MOUNTED ON THE SHAFT, THE ENDS OF THE SHAFTPROTRUDING BEYOND THE ROCKER ARM; ALIGNED, TRANSVERSE SLOTS FORMED INTHE AXIALLY OUTWARDLY FACING SURFACES OF THE PROTRUDING ENDS OF THESHAFT; A RECIPROCALLY MOVABLE PUSH ROD ABUTTING ON THE UNDERSIDE OF THEROCKER ARM ADJACENT ONE END OF THE ROCKER ARM AND ADAPTED TO PIVOT THEROCKER ARM ON THE SHAFT; A SPRING HAVING A PAIR OF PARALLEL COILS SPACEDAPART FROM EACH OTHER AND ADAPTED TO PRODUCE A TORQUE; A FIRST,SUBSTANTIALLY STRAIGHT LEG EXTENDING FROM EACH OF THE COILS, EACH OFSAID LEGS BEING ADAPTED TO BE RECEIVED IN A TRANSVERSE SLOT IN ANOPPOSIE END OF THE SHAFT; A SECOND LEG EXTENDING FROM EACH OF SAIDCOILS, SAID SECOND LEG BEING DISPOSED SUBSTANTIALLY PARALLEL TO EACHOTHER; AND A TRANSVERSE YOKE INTERCONNECTING THE SECOND LEGS AND ADAPTEDTO OVERLIE AND ABUT ON THE ROCKER ARM ABOVE THE ABUTMENT OF THE PUSH OFROD THEREON, SAID YOKE BEING IN TORQUE BIASING ENGAGEMENT WITH THEROCKER ARM SO AS TO CAUSE THE ROCKER ARM TO FOLLOW THE PUSH ROD IN ITSRECIPROCAL MOVEMENT.